@article{huang2015bidirectional,
  title={Bidirectional LSTM-CRF Models for Sequence Tagging},
  author={Zhiheng Huang and Wei Xu and Kai Yu},
  journal={CoRR},
  year={2015},
  volume={abs/1508.01991},
  url={https://arxiv.org/pdf/1508.01991.pdf}
}